Brownells Brn-4 Stripped Barrel,10.4'' Medium, 1-7, 1/2''-28,Blk Nitride

The Brownells BRN-4 Stripped Barrel in 10.4" medium profile is a modern take on a historically hard-to-find part: a genuine HK 416-compatible barrel built to early-generation HK 416 upper specifications. Machined by Faxon and finished in black nitride for durability and easy maintenance, this barrel gives you a reliable foundation for a short, handy 5.56 NATO or .223 Remington rifle without the weight penalty of a heavy profile. Whether you're building a compact patrol rifle, a short-range hitter for home defense, or an overlander's truck gun, this stripped barrel pairs seamlessly with the rest of the BRN-4 system and lets you finish the build to your exact specs.

The 1-7 twist rate is a proven all-rounder, stabilizing everything from 55-grain varmint rounds to heavier 77-grain loads reliably. The 1/2"-28 muzzle threads accept any standard AR-pattern muzzle device—suppressor, brake, or flash hider—giving you full control over how your rifle sounds and performs. The medium contour cuts weight compared to the heavy profile while maintaining the rigidity you need for reliable semi-auto function, making the rifle feel noticeably lighter in the hand without sacrificing durability.

Installation is straightforward: the extended barrel extension mates securely to the upper receiver using the BRN-4 barrel nut, torqued to 50–80 ft/lbs. All BRN-4 barrels use the same piston rod assembly, so you'll just need to match your gas block to the barrel length. Black nitride coating protects both bore and exterior surfaces from corrosion and makes cleanup after a hard day at the range or in the field quick and simple.

Key Features

• 10.4" medium profile—lighter than heavy contour, maintains rigidity
• 1-7 twist rate for reliable stabilization across a wide ammo range
• 1/2"-28 muzzle threads for standard AR muzzle devices
• HK 416-compatible design, machined by Faxon for early-generation uppers
• Black nitride finish—hard, durable, and easy to clean inside and out
• Extended barrel extension for secure upper receiver fit
• 5.56 NATO and .223 Remington capable

Specifications

Frequently Asked Questions

What gas block do I need for this barrel?

All BRN-4 barrels use the same piston rod assembly. For the 10.4" length, you'll need to select the appropriate BRN-4 gas block for that barrel length (reference 078-000-708 or 078-000-709 depending on your setup). Grab the gas block coil pins (430-103-127) for assembly as well.

What barrel nut do I use?

Use the BRN-4 barrel nut (part 430-100-141), torqued to 50–80 ft/lbs. The extended barrel extension on the BRN-4 design ensures a robust fit to the upper receiver.

Is this barrel stripped or does it come assembled?

This is a stripped barrel—the bare barrel component only. You'll need to source a barrel nut, gas block, piston rod assembly, and other components to complete your build. The BRN-4 system parts are designed to work together.

What muzzle devices can I attach?

The 1/2"-28 threads accept any standard AR-pattern muzzle device: suppressors, muzzle brakes, flash hiders, and combination devices. Your choice depends on your intended use and budget.